1. Field of the Invention
The present invention relates to a manufacturing method in which a rare-earth oxide can be sintered at low temperature.
2. Description of Background Art
As a common ceramic, alumina (Al2O3) or zirconia (ZrO2) have been used. Although there is known amorphous formation, single-crystal growth and thin-film formation as the formation method, sintering is the most common method. Also, in order to easily complete sintering, a sintering aid is used.
The present inventors have paid attention to boron oxide (B2O3) as a sintering aid. Patent Document 1 and Non-patent Document 1 can be listed as a background art material in which boron oxide (B2O3) is used as a sintering aid.
Patent Document 1, Japanese Patent Application Publication No. 2000-239065, has disclosed that yttria (Y2O3) powder is formed by cold isostatical press (CIP), the formed body is fired at 1400-1800° C., cooled, and thereafter heated at 1400-2000° C. in the presence of a boron compound (B2O3), so that a dense yttria (Y2O3) sintered body can be obtained. According to Patent Document 1, it is assumed that the dense sintered body can be obtained because the presence of a boron compound promotes sintering due to diffusion of B2O3 inside the body.
Non-patent Document 1, Production of Transparent Yttrium Oxide by HIP sintering, The Ceramic Society of Japan, 2004, Preprint 2G09, has disclosed that yttria (Y2O3) powder is formed by CIP (140 MPa), first sintering is performed to the formed body at 1400-1700° C., BN is sprayed on the sintered body, and second sintering is performed by HIP (140 MPa, 1400-1700° C.), so that an yttria (Y2O3) sintered body having excellent transparency can be obtained.
However, according to these documents, firing at relatively high temperature such as 1700-2000° C. is required to obtain a sintered body having small porosity, or a complicated manufacturing process such as HIP processing after first sintering is required to obtain a sintered body.
An object of the present invention is to provide a rare-earth oxide sintered body and a corrosion-resistance material having high density and excellent plasma-resistance which can be manufactured easily at low temperature, and a manufacturing method thereof.